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service enhancement or replacement without affecting the communication process
as a whole. To this end, the IEEE's standards development focuses on distinct
functional categories. These categories are as follows:
• General Architecture and Internetworking—This category covers bridging,
switching, Layer 2 addressing, and management. These standards are
developed by the 802.1 subcommittee. The majority of these standards
define how OSI-RM Layer 2 transmission protocols will function in an
operational and implementation way.
• Logical Link Control (LLC)—LLC provides the software interface between the
Layer 2 transmission protocol and the Layer 3 networking protocol. The LLC
standard was developed by the 802.2 subcommittee. LLC is used by all the
IEEE standards-based protocols and several non-IEEE protocols. It is
classified as part of OSI Layer 2 functionality. Nevertheless, it functions as a
distinct service interface to manage the actual delivery of data between
end-stations. Data link (the term used to describe this function with WAN
protocols) or link control is provided differently, depending on the
transmission protocol, but the service's function is the same regardless.
• Media Access Control (MAC)—MAC is responsible for the data transmission
frame format, data integrity checking, and managing station access to the
physical transmission medium (for example, collision detection in the case of
Ethernet). For each MAC protocol there is a separate 802 subcommittee.
Currently eight different IEEE subcommittees develop MAC standards for
physical media and wireless communication. In terms of the LAN, the 802.3
subcommittee develops standards for Ethernet, and 802.5 develops
standards for Token Ring. The MAC subcommittee standards encompass
both OSI-RM Layers 1 and 2 functionality. The MAC service interface resides
in Layer 2, and the PHY service interface—which defines the signaling and
encoding used to transmit the MAC interface frames—resides at Layer 1. The
MAC protocol is often used to generalize the Layer 2 function because it
represents for the most part the common denominator between the PHY and
LLC service layers of the data transmission function.
• Security—All security issues and standards dealing with the 802.x standards
are developed by the 802.10 subcommittee.
The development and implementation of standards-based technologies assures
compatibility between networking products manufactured by different product
vendors. The standards development process is a collaborative effort between the
IEEE, networking product vendors, and other interested parties. Actually, quite
often, vendors develop proprietary implementations of technologies and then offer
them as a standard or as an addition to the existing standard. When a new
technology is developed, a new IEEE subcommittee is formed to codify a standard.
In the event that an innovation is made to an existing IEEE standard, it is handled
as a subcommittee's supplemental project. Each supplement is assigned a one- or
two-letter designator. For example, the IEEE standard for 100Mbps Fast Ethernet is